In this paper, a novel 800mV beta-multiplier reference current source circuit is presented. In order to cope with the narrow input common-mode range of the Opamp in the reference circuit, the resistive voltage divider was employed. High gain Opamp was designed to compensate for the intrinsic low output resistance of the MOS transistors. The proposed reference circuit was designed in a standard 0.18µm CMOS process with nominal V_th of 420mV and -450mV for n-MOS and p-MOS transistor, respectively. The total power consumption including Opamp is less than 50µW.